A. Field of the Invention
This invention relates to wire line removable ball type subsurface safety valves utilized to control flow at a subsurface location in a well.
B. The Prior Art
The present invention is related to wire line removable ball type subsurface safety valves referred to by Otis Engineering Corporation as type "A", as illustrated on page 3821 of the 1968-1969 Composite Catalog of Oil Field Equipment and Services.
These valves have been extensively used in wells for many years and are still being used today. In the intervening years, however, improvements have been made in the design of the ball type subsurface safety valve. One of the more significant improvements has been the provision of "pump through" capability. That is to say, in the event there is a loss of control pressure, the ball valve will rotate to the closed position, with the operator then being able to pump down fluids at a pressure sufficient to unseat the ball and thus, allowing the well to be killed, if that is desired.
Prior valves such as the type "A" valve do not have a pump through feature or means to utilize a pump down fluid to actuate the ball valve to the full open position. Although fluid could be pumped through the valve from the surface the valve only partially opens when pumping through it and thus, it is possible to cut the seat and/or ball and damage it. For this reason, such pump down of fluids were done only as an emergency operation.
An object of the present invention is to provide a valve of the general character described above modified to provide a pump through capability.
Another object is to provide a valve of the general character described above which is modified in such manner as to avoid the necessity of replacing or redesigning the valve in order to have a pump through capability.
Yet another object of the present invention is to provide a valve of the general character above-described wherein the pump-through fluid is first utilized to move the valve into a full open position, after which said fluid flows through the open valve to the area therebelow.
Another object is to provide a valve of the general character described wherein the pump-through fluid actuates an actuator or control frame to move the valve into a full open position and at the same time closes off the fluid port which normally conducts pressure fluid to the valve to control its operation.
Other objects, advantages and features of this invention will be apparent to one skilled in the art upon a consideration of the written specification, the attached claims and the annexed drawings.